Abstract
The conventional method to determine the lifetime of solar p modes is via the measurement of the width of the p-mode line profile in power spectra. Nevertheless, this approach can be applied only for low- and intermediate-degree modes. For high-degree modes, mode blending prevents us from using this method. In this study, we develop a new method to measure high-degree p-mode lifetimes. We adopt a new approach to determine the rate of decay in amplitude of wave function for each mode. The wave function of each p-mode is computed by Fourier decomposing the measured wave function associated with a particular radial order. Fourier decomposing in the spatial domain allows us to study the decay of wave function in the time domain for each wavenumber and radial order, namely, the decay time of each mode. On the other hand, the decay length of each mode can be determined with Fourier decomposition of wave function in the temporal domain. The consistence between the decay time and the decay length serves as a check for this method. This method allows us to study the lifetime of p modes up to ℓ = 1332 using helioseismic data taken with HMI (Helioseismic and Magnetic Imager) onboarded the Solar Dynamical Observatory.